Novel 5-hydroxymethyl oxazolidinones, the method of preparing them and their application in therapeutics

ABSTRACT

There are disclosed 3-substituted phenyl-5-hydroxymethyl oxazolidinones which possess anti-depressant properties. The compounds are prepared by cyclizing, with ethyl carbonate, 1-substituted phenylamino-2,3-propanediol compounds.

The present invention concerns novel 5-hydroxymethyl oxazolidinones, the method of preparing them and their application in therapeutics.

The compounds in question correspond more exactly to the formula: ##STR1## in which R represents: (1) an m-dimethylamino; p-n pentylamino; p-trifluoromethyl; p-phenoxymethyl group whose phenyl nucleus may be substituted in position 3 by a nitro group; p-(m-chlorophenylethyl) or p-styryl (trans) group;

(2) an --SR₁ group situated in para position and in which R₁ represents an alkyl group having 5 carbon atoms or an acetylmethylthio group;

(3) an --OR₂ group situated in para position in which R₂ represents:

an isopentyl, neopentyl, 3,3-dimethylbutyl or 2-ethylbutyl group,

a cycloalkylmethyl group in which the cycloalkyl group comprises from 3 to 7 carbon atoms or a cycloalkylethyl group in which the cycloalkyl group comprises 5 or 6 carbon atoms,

a pentene-4 yl group,

a 1-cycloalkene methyl group comprising 6 or 7 carbon atoms, a 1-methyl cyclopentylmethyl or 1,4-cyclohexadiene methyl group, or

a 1,3-dioxolan-2-yl methyl; 1,3-diotholanne-2 yl methyl; 1,3-oxathiolan-2-yl methyl; 1,3-dithian-2-yl methyl; tetrahydropyran-2-yl methyl; tetrahydropyran-3-yl methyl; or tetrahydropyran-4 yl methyl group;

(4) a substituted benzyloxy group situated in para position and of formula: ##STR2## in which R₃ represents an element chosen from the following: o-cyano, m-chloro, m-bromo, m-iodo, m-nitro, m-cyano, p-acetamido, m-amino, p-NHCOOCH₃, p-NHCOC₂ H₅ ;

(5) a disubstituted benzyloxy group situated in para position and of formula: ##STR3## in which the couple (R₄,R₅) assumes a value chosen from the following: (3--Cl, 4--Cl), (2--Cl, 4--Cl), (3--Cl, 5--Cl), (3--Cl, 4--F), (3--NO₂, 4--Cl), (3--Cl, 4--NO₂), (3--CN,4--F), (3NO₂, 4--F), (3--NO₂, 5--CN), (3--NO₂, 5--Cl);

(6) an heterocyclic methyloxy chain situated in para position and of formula:

    Het--CH.sub.2 O--

in which Het represents one of the following radicals: 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-thienyl, 3-thienyl, 2-furyl, 3-furyl, 2-pyrazinyl;

(7) a --COR₆ chain situated in para position and in which R₆ represents an alkyl group comprising from 2 to 3 carbon atoms;

(8) an --O--CH₂ --CO--R₇ chain situated in meta or para position and in which R₇ represents an alkyl group comprising from 1 to 3 carbon atoms;

(9) an --O--(CH₂)n--CN chain situated in meta or para position and in which n is equal to 1, 2, 3 or 4; or

(10) a chain situated in para position chosen from the following: methoxymethyloxy, 2-morpholino ethoxy; acetylmethyloxy oxime.

The compounds of formula (I) are obtained:

(a) by cyclizing through the action of ethyl carbonate preferably in the presence of a base and an organic solvent, a 1-phenylamino 2,3-propanediol of formula: ##STR4## in which R₈ represents:

an m-dimethylamino, p-phenoxymethyl, p-trifluoromethyl, p-(m-chlorophenylethyl) or p-styryl (trans) group,

an --SR₁ group situated in para position and in which R₁ represents an alkyl group comprising 5 carbon atoms, or

a --COR₆ chain situated in para position and in which R₆ represents an alkyl group comprising from 2 to 3 carbon atoms, which leads to compounds of formula: ##STR5## where R₈ has the same meaning as above;

(b) by cyclizing, through the action of ethyl carbonate, 1-phenylamino 2,3-propanediol of formula: ##STR6## which leads to the compound of formula: ##STR7## which is then subjected to the action of hydrogenolysis in alcohol in the presence of palladium on charcoal, to obtain the compound of formula: ##STR8## which is condensed, preferably to reflux in acetone or acetonitrile and in the presence of potassium carbonate, with a product corresponding to one of the following formulae: ##STR9## in which R₉ :

has the same significance as R₂ in formula (I) except the 1,3-dithiola-2-yl methyl; 1,3-oxathiolan-2-yl methyl and 1,3-dithian-2-yl methyl groups, or

represents:

a substituted benzyl group of formula: ##STR10## where R₃ has the same significance as in formula (I),

a disubstituted benzyl group of formula: ##STR11## where R₄ and R₅ have the same significance as in formula (I),

an heterocyclic methyl chain of formula:

    Het-CH.sub.2 --

where Het has the same significance as in formula (I),

a --CH₂ --CO--R₇ chain in which R₇ has the same significance as in formula (I), or

a group chosen from the following: methoxymethyl, 2-morpholino ethyl, cyanomethyl, 3-cyano propyl, 4-cyano butyl; which leads to the compounds of formula: ##STR12## where R₉ has the same significance as above;

(c) by cyclizing, through the action of ethyl carbonate, 1-phenylamino 2,3-propanediol of formula: ##STR13## which leads to the novel compound of formula: ##STR14## which is subjected to selective hydrogenolysis in ethanol in the presence of palladium on charcoal, preferably at room temperature, to provide the novel compound of formula: ##STR15## which is condensed with acrylonitrile of formula:

    CH.sub.2 =CH--CN                                           (XII)

in the presence of triton B, which leads to the novel compound of formula: ##STR16## which is then hydrogenolysed in ethanol in the presence of palladium on charcoal and preferably of a few drops of hydrochloric ethanol, to obtain the compound of formula: ##STR17##

(a) by condensing the compound of formula: ##STR18## obtained at point (b) above, with hydroxylamine hydrochloride in aqueous ethanol, which leads to the compound of formula: ##STR19##

(e) by cyclizing, through the action of ethyl carbonate, the compound of formula: ##STR20## which leads to the novel compound of formula: ##STR21## which is then hydrolyzed in the presence of concentrated hydrochloric acid in tetrahydrofuran, to obtain the compound of formula: ##STR22##

(f) by cyclizing, through the action of ethyl carbonate, the compound of formula: ##STR23## which leads to the novel compound of formula: ##STR24## which is then subjected to simultaneous reduction and hydrogenolysis, in ethanol in the presence of palladium on charcoal and preferably of hydrochloric ethanol 6,5 N to obtain the novel compound of formula: ##STR25## which is condensed with the n-pentyl bromide of formula:

    C.sub.5 H.sub.11 n--Br                                     (XIX)

in butanol in the presence of potassium carbonate, which leads to the compound of formula: ##STR26##

(g) by cyclizing the compound of formula: ##STR27## in the presence of ethyl carbonate, particularly in dioxane, by subjecting the compound thus obtained of formula: ##STR28## to the action of the tert butyric acid chloride, particularly in pyridine, by reducing the resulting compound of formula: ##STR29## with sodium borohydride, particularly in methanol, and by subjecting the compound obtained of formula: ##STR30## to the action of methyl chloride, particularly in methylene chloride, which leads to the compound of formula: ##STR31## where Ms represents the mesyl radical, which is reacted with metanitrophenol in the presence of sodium hydride, the compound obtained of formula: ##STR32## being hydrolyzed, preferably in the presence of a base such as potash, particularly in methanol, which leads to the compound of formula: ##STR33## and,

(h) by condensing diethylacetal bromoacetaldehyde of formula: ##STR34## on 3-p-hydroxylphenyl 5-hydroxymethyl 2-oxazolidinone of formula (V') obtained in accordance with point (b) above, in the presence of sodium hydride and an organic solvent such as DMF for example, the resulting compound of formula: ##STR35## being reacted with a compound of formula: ##STR36## in which the couple (n, X) may assume the following values: (1, sulfur), (1, oxygen), (2, sulfur), preferably in the presence of boron trifluoride etherate in methylene chloride, which leads to the compounds of formula: ##STR37## where R'₂ designates a 1,3-dithiolan-2-yl methyl; 1,3-oxathiolan-2-yl methyl; or 1,3-dithian-2-yl methyl group.

The compounds of formula (II) are, for their part, obtained by condensation in methanol or ethanol of anilines of formula: ##STR38## in which R₈ has the same significance as in formula (II), with glycidol of formula: ##STR39##

The compounds of formulae (III), (IX), (XIV) and (XVI) are prepared by the same method but using the corresponding anilines.

It should further be noted that the compounds of formulae (I), (XV) and (XVIII) will be regrouped, in the claims, under formula (I').

The examples below are given by way of illustration of the invention.

EXAMPLE 1 5-hydroxymethyl 3-p-trifluoromethylphenyl 2-oxazolidinone (I)--Code number 770 152

A mixture of 46 g (0.195 mole) of 3-paratrifluoromethylphenylamino 1,2-propanediol (II), 23.6 g (0.2 mole) of ethyl carbonate and a few drops of a 5% methanolic solution of soda methylate in 400 ml of toluene were heated at 105° C. for an hour. Then, the solvents were evaporated and the residue chromatographed on a silica column (eluent:CHCl₃), this operation being followed by recrystallization in isopropyl ether.

Yield: 20%.

Melting point: 88° C.

Empirical formula: C₁₁ H₁₀ F₃ NO₃.

Molecular weight: 261,19.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    50.58    3.86     5.36                                       Obtained (%)      50.74    3.83     5.32                                       ______________________________________                                    

The compounds with the following code numbers and shown in Table I below can be obtained in the same way: 770 365-770 423-770 696-770 180-770 155-771 181-780 564.

EXAMPLE 2 5-hydroxymethyl 3-meta-cyanomethyloxyphenyl 2-oxazolidinone--Code number: 770 231

1st step: 5-hydroxymethyl 3-m-hydroxyphenyl 2-oxazolidinone (V)

A solution of 132.5 g (0.44 mole) of 5-hydroxymethyl 3-m-benzyloxyphenyl 2-oxazolidinone prepared by an operational mode similar to that of example 1, in 1.5 liter of alcohol in the presence of 13 g of palladium on 10% charcoal was hydrogenolized in an autoclave, between 45° and 50° C., at a pressure of 2 kg for 6 hours. The solution was filtered and the filtrate evaporated and recrystallized in isopropyl alcohol.

2nd step: 5-hydroxymethyl 3-m-cyanomethyloxyphenyl 2-oxazolidinone--Code number 770 231

A mixture of 15 g (0.07 mole) of 5-hydroxymethyl 3-m-hydroxyphenyl 2-oxazolidinone prepared in the previous step, 7.6 g (0.1 mole) of chloroacetonitrile, 38 g (0.28 mole) of potassium carbonate and 1 g of potassium iodide in 450 ml of acetone was brought to reflux for 8 hours. The mixture was filtered, the filtrate was evaporated and the residue was recrystallized in absolute alcohol.

Yield: 71%.

Melting point: 110° C.

Empirical formula: C₁₂ H₁₂ N₂ O₄.

Molecular weight: 248,23.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    58.06    4.87     11.29                                      Obtained (%)      58.08    4.90     11.35                                      ______________________________________                                    

In the same way the compounds, shown in table I below, with the following code numbers can be obtained: 770 388-770 788-770 467-770 466-770 196-770 154-760 904-750 601-760 557-770 234-770 318-770 222-770 569-770 268-770 354-770 416-770 572-770 672-770 790-770 789-770 298-770 221-770 299-770 673-770 845-770 230-770 889-771 082-771 249-;b 771 246-771 197-780 030-771 245-770 949-780 076-770 984-770 962-780 034-770 900-771 301-771 321-771 240-780 182-780 443-770 955-771 125-771 199-770 979-771 067-780 259-780 562.

EXAMPLE 3: 3-(2-paracyano ethoxyphenyl) 5-hydroxymethyl 2-oxazolidinone Code number: 770 131

1st step: 3-(p-benzyloxyphenyl) 5-benzyloxymethyl 2-oxazolidinone--Code number: 760 431

This compound is prepared by using a method identical to that of example 1, from the appropriate propanediol:

Yield: 80%.

Melting point: 126° C.

Empirical formula: C₂₄ H₂₃ NO₄.

Molecular weight: 389,43.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    74.02    5.95     3.60                                       Obtained (%)      73.87    6.1      3.89                                       ______________________________________                                    

2nd step: 3-(p-hydroxyphenyl) 5-benzyloxymethyl 2-oxazolidinone--Code number: 760 484

A suspension of 18 g (0.046 mole) of the compound prepared in the previous steps and 2 g of palladium on 10% charcoal in 400 ml of absolute alcohol was hydrogenolized in an autoclave, at room temperature, under a pressure of 4 to 5 kg of hydrogen. Then, it was filtered, the solvent evaporated and recrystallized in absolute alcohol.

Yield: 73%.

Melting point: 153° C.

Empirical formula: C₁₇ H₁₇ NO₄.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    68.21    5.73     4.68                                       Obtained (%)      68.38    5.62     4.46                                       ______________________________________                                    

3rd step: 3-(2-p-cyanoethoxy phenyl) 5-benzyloxymethyl 2-oxazolidinone--Code number: 760 993

A solution of 13 g (0.03 mole) of the compound prepared in the previous step, in 45 g (0.86 mole) of acrylonitrile in the presence of 1 ml of triton B (40% in methanol) was brought to reflux for 15 hours. Then, the excess acrylonitrile was evaporated, the residue was taken up in 100 ml of NaOH N, filtered, the precipitate was washed in water than in ether and recrystallized in methanol.

Yield: 60%.

Melting point: 112° C.

Empirical formula: C₂₀ H₂₀ N₂ O₄.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    68.17    5.72     7.95                                       Obtained (%)      67.89    5.66     8.21                                       ______________________________________                                    

4th step: 3-(2-p-cyano ethoxyphenyl) 5-hydroxymethyl 2-oxazolidinone--Code number: 770 131

A suspension of 3.5 g (0.01 mole) of 3-(2-p-cyano-ethoxyphenyl) 5-benzyloxymethyl 2-oxazolidinone prepared in the preceeding step, 0.4 g of palladium on 10% charcoal and 0.05 ml of hydrochloric ethanol 7.5 N, in 250 ml of dioxanne was hydrogenolized in an autoclave at a pressure of 1 kg of hydrogen and at room temperature. It was filtered and the residue was purified by chromatography on a silica column. Eluated by the 50/50 chloroform-acetone mixture, then recrystallized in absolute alcohol; 1 g of expected product was obtained.

Yield: 39%.

Melting point: 131° C.

Empirical formula: C₁₃ H₁₄ N₂ O₄.

    ______________________________________                                         Elementary analysis                                                                              C        H        N                                          ______________________________________                                         Calculated (%)    59.53    5.38     10.68                                      Obtained (%)      59.06    5.24     10.37                                      ______________________________________                                    

EXAMPLE 4: oxime of 3-(p-acetylmethyloxyphenyl) 5-hydroxymethyl 2-oxazolidinone--Code number: 770 126

A solution of 7 g (0.026 mole) of 3-(p-acetylmethyloxy) 5-hydroxymethyl 2-oxazolidinone (code number 760 652) prepared in accordance with example 2, and 2.1 g (0.03 mole) of hydroxylamine hydrochloride, in a mixture of 120 ml of ethanol and 6 ml of water was maintained for 2 hours at room temperature. Then the solvent was evaporated, the residue was taken up in water, filtered and recrystallized in 96° alcohol.

Yield: 75%.

Melting point: 164° C.

Empirical formula: C₁₃ H₁₆ N₂ O₅.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    55.71    5.75     10.00                                      Obtained (%)      55.44    5.70     10.09                                      ______________________________________                                    

EXAMPLE 5: 3-(p-acetylmethylthiophenyl) 5-hydroxymethyl 2-oxazolidinone Code number: 770 501

1st step: 2-methyl p-[3-(5-hydroxymethyl oxazolidinone)]2-phenylmercapto 1,3-dioxan--Code number: 770 500

This compound is prepared by using an operational mode identical with that of example 1 from appropriate propanediol.

Melting point: 140° C.

Empirical formula: C₁₅ H₁₉ NO₅ S.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    55.37    5.89     4.31                                       Obtained (%)      55.36    5.79     4.09                                       ______________________________________                                    

2nd step: 3-(p-acetylmethylthiophenyl) 5-hydroxymethyl 2-oxazolidinone--Code number: 770 501

A solution of 10.5 g (0.032 mole) of the compound prepared in the preceeding step in 200 ml of tetrahydrofurane and 10 ml of hydrochloric acid were brought to reflux for 30 minutes. Then, the solvent was evaporated and the residue was taken up in water filtered and recrystallized in methanol.

Yield: 53%.

Melting point: 116° C.

Empirical formula: C₁₃ H₁₅ NO₄ S.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    55.50    5.37     4.98                                       Obtained (%)      55.32    5.33     4.68                                       ______________________________________                                    

EXAMPLE 6: 3-p-n pentylaminophenyl 5-hydroxymethyl 2-oxazolidinone Code number: 770 328

1st step: 5-benzyloxymethyl 3-p-nitrophenyl 2-oxazolidinone--Code number: 770 151

This compound is obtained by using an operational mode identical to that of example 1, from appropriate propanediol.

Yield: 78%.

Melting point: 125° C.

Empirical formula: C₁₇ H₁₆ N₂ O₅.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    62.19    4.91     8.53                                       Obtained (%)      61.84    4.87     8.57                                       ______________________________________                                    

2nd step: 3-p-aminophenyl 5-hydroxymethyl 2-oxazolidone hydrochloride--Code number: 770 221

A suspension of 25 g (0.076 mole) of the compound prepared in the preceding step, 2.5 g of palladium on 10% charcoal and 12.5 ml of hydrochloric ethanol 6.5 N in 600 ml of absolute ethanol were brought to 50° C., in an autoclave, at a pressure of 3 kg of hydrogen for 2 hours. Then it was filtered, the solvent was evaporated and the residue recrystallized in methanol.

Yield: 64%.

Melting point: 200° C.

Empirical formula: C₁₀ H₁₃ ClN₂ O₃.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    49.09    5.36     11.23                                      Obtained (%)      48.63    5.27     11.25                                      ______________________________________                                    

3rd step: 3-p-n pentylaminophenyl 5-hydroxymethyl 2-oxazolidinone Code number: 770 328

A suspension of 6.1 g (0.025 mole) of the compound prepared in the preceding step, 4.5 g (0.03 mole) of n-pentyl bromide, 10 g of potassium carbonate and 0.1 g of sodium iodide in 100 ml of butanol was brought to reflux for 12 hours. It was filtered, the solvent was evaporated and crystallized in a mixture of ether and isopropyl alcohol.

Yield: 10%.

Melting point: 124° C.

Empirical formula: C₁₅ H₂₂ N₂ O₃.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    64.72    7.97     10.07                                      Obtained (%)      64.47    7.97     10.02                                      ______________________________________                                    

EXAMPLE 7 3-para (metanitrophenoxymethyl) phenyl 5-hydroxymethyl 2-oxazolidinone--Code number: 771 263

1st step: 3-paraformylphenyl 5-hydroxymethyl 2-oxazolidinone Code number: 770 054

A mixture of 65.4 g of 3-paraformylanilino 1,2-propanediol, 43.6 g of diethyl carbonate and 16 ml of sodium methylate (10% solution in methanol) in 830 ml of dioxan was brought to reflux (by distilling the alcohol formed). Then it was filtered, the filtrate evaporated and the residue taken up in chloroform and washed with a dilute hydrochloric acid solution. Then, it was dried, the solvent evaporated and the residue chromatographed on a silica column, which gave the product desired.

Yield: 23%.

Melting point: 123° C.

Empirical formula: C₁₁ H₁₁ NO₄.

Molecular weight: 221,21.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    59.72    5.01     6.33                                       Obtained (%)      59.49    4.66     6.20                                       ______________________________________                                    

2nd step: 3-paraformylphenyl ter-butylcarbonyloxymethyl 2-oxazolidinone Code number: 771 213

To a solution of 15.5 g of the compound prepared in the preceding stage in 180 ml of pyridine, there was slowly added 12.2 ml of tert-butyric acid chloride. After 1 hour at room temperature, it was diluted with water and the precipitate formed was filtered, dried and recrystallized in ethanol.

Yield: 90%.

Melting point: 134° C.

Empirical formula: C₁₆ H₁₉ NO₅.

Molecular weight: 305,32.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    62.94    6.27     4.59                                       Obtained (%)      62.64    6.57     4.46                                       ______________________________________                                    

3rd step: 3-para-hydroxymethylphenyl 5-tert-butylcarbonyloxymethyl 2-oxazolidinone Code number: 771 214

To a suspension of 11.3 g of the compound prepared in the preceding stage there was slowly added 0.7 g of sodium borohyrdride. After 10 minutes, the solvent was evaporated, the residue was taken up in ethyl acetate, washed with water and dried, the solvent was evaporated and the residue was recrystallized in a mixture of ether and isopropanol.

Yield: 80%.

Melting point: 102° C.

Empirical formula: C₁₆ H₂₁ NO₅.

Molecular weight: 307,34.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    62.52    6.89     4.56                                       Obtained (%)      62.58    7.01     4.32                                       ______________________________________                                    

4th step: 3-para (metanitrophenoxymethyl) phenyl 5-hydroxymethyl 2-oxazolidinone--Code number: 771 263

To a solution of 11.7 g of the compound obtained in the preceding step in 150 ml of methylene chloride there was added 10.6 ml of triethylamine and 6 ml of mesyl chloride, at 0° C. Then, after 3 hours contact at room temperature, it was diluted with water, decanted and the organic phase evaporated. The residue obtained (dissolved in 100 ml of dimethylformamide) was added to a solution of 3.7 g of metanitrophenol and 1.25 g of sodium hydride (at 50%) in 50 ml of dimethylformamide and the mixture was brought to 60° C. for 3 hours. Then, the mixture was poured into water, extracted with ethyl acetate and dried; the solvent was evaporated and the residue was treated with a solution of 0.6 g of potash in 120 ml of methanol. After 1 hour of reflux, the mixture was poured into water and the precipitate obtained was filtered and then recrystallized in methanol, then in ethanol.

Yield: 44%.

Melting point: 142° C.

Empirical formula: C₁₇ H₁₆ N₂ O₆.

Molecular weight: 344,31.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    59.30    4.68     8.14                                       Obtained (%)      59.44    4.38     7.99                                       ______________________________________                                    

EXAMPLE 8 3-para-[(1,3-dithiolan-2yl)methoxy]phenyl 5-hydroxymethyl 2-oxazolidinone--Code number: 780 080

1st step: 3-para (2,2diethoxy) ethoxyphenyl 5-hydroxymethyl 2-oxazolidinone.--Code number: 771 049

To a solution of 21 g of 3-para-hydroxy-phenyl-5-hydroxymethyl 2-oxazolidnone in 200 ml of dimethylformamide was added 4.8 g of sodium hydride (at 50%) then 30 ml of acetal diethyl bromoacetaldehyde. The mixture was brought to 50° C. for 13 hours, then it was poured into chilled water, extracted with ethyl acetate, washed with water, the solvent was evaporated and the residue chromarographed on a silica column. Eluated with the mixture 99% CHCl₃ -1% CH₃ OH, 17 g of the desired product were obtained.

Melting point: 90° C.

Empirical formula: C₁₆ H₂₃ NO₆.

Molecular weight: 325,35.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    59.06    7.13     4.31                                       Obtained (%)      58.82    7.15     4.22                                       ______________________________________                                    

2nd step: 3-para[(1,3-dithiolan-2-yl)-methoxy]phenyl 5-hydroxymethyl 2-oxazolidinone--Code number: 780 080

A solution of 2.9 g of the compound prepared in the preceding step, 1.2 ml of 1,2-ethanedithiol and 1 ml of boron trifluoride etherate in 35 ml of methylene chloride is maintained at room temperature during 45 mn. Then, it was diluted with ether and the precipitate formed was filtered.

Yield: 60%.

Melting point: 160° C.

Empirical formula: C₁₄ H₁₇ NO₄ S₂.

Molecular weight: 327,42.

    ______________________________________                                         Elementary analysis:                                                                             C        H        N                                          ______________________________________                                         Calculated (%)    51.35    5.23     4.28                                       Obtained (%)      51.51    5.28     4.00                                       ______________________________________                                    

By using the same process but from the corresponding reagents, the compounds with code numbers 780 077 and 780 112, shown in Table 1 below, were obtained.

                                      TABLE I                                      __________________________________________________________________________      ##STR40##                                                                                                         Melting  Elementary Analysis               Code                  Empirical                                                                              Molecular                                                                            point                                                                               Yield                                                                              Calculated                                                                              Obtained (%)             number                                                                                R              formula weight                                                                               (°C.)                                                                        (%) C  H  N  C  H  N                  __________________________________________________________________________     77 0365                                                                             4-COEt           C.sub.13 H.sub.15 NO.sub.4                                                             249,26                                                                               186  62  62,64                                                                             6,07                                                                              5,62                                                                              62,87                                                                             6,25                                                                              5,41               77 0423                                                                             4-COC.sub.3 H.sub.7 n                                                                           C.sub.14 H.sub.17 NO.sub.4                                                             263,28                                                                               120  68  63,86                                                                             6,51                                                                              5,32                                                                              63,75                                                                             6,67                                                                              5,20               77 0152                                                                             4 CF.sub.3       C.sub.11 H.sub.10 F.sub.3 NO.sub.3                                                     261,19                                                                               88   20  50,58                                                                             3,86                                                                              5,36                                                                              50,74                                                                             3,83                                                                              5,32               77 0696                                                                              ##STR41##       C.sub.17 H.sub.17 NO.sub.4                                                             299,31                                                                               140  10  68,21                                                                             5,73                                                                              4,68                                                                              68,22                                                                             5,57                                                                              4,85               77 0388                                                                              ##STR42##       C.sub.14 H.sub.17 NO.sub.4                                                             263,28                                                                               134  76  63,86                                                                             6,51                                                                              5,32                                                                              63,91                                                                             6,57                                                                              5,30               77 0788                                                                              ##STR43##       C.sub.15 H.sub.19 NO.sub.4                                                             277 ,31                                                                              108  48  64,96                                                                             6,91                                                                              5,05                                                                              64,66                                                                             6,89                                                                              4,94               77 0467                                                                              ##STR44##       C.sub.16 H.sub.21 NO.sub.4                                                             291,34                                                                               130  30  65,96                                                                             7,27                                                                              4,81                                                                              66,04                                                                             7,24                                                                              4,53               77 0466                                                                              ##STR45##       C.sub.16 H.sub.19 NO.sub.4                                                             289,32                                                                               119  81  66,42                                                                             6,62                                                                              4,84                                                                              66,14                                                                             6,44                                                                              4,84               77 0196                                                                             4 O(CH.sub.2).sub.3CHCH.sub.2                                                                   C.sub.15 H.sub.19 NO.sub.4                                                             277 ,31                                                                              102  51  64,96                                                                             6,91                                                                              5,05                                                                              64,93                                                                             7,00                                                                              5,18               77 0154                                                                              ##STR46##       C.sub.15 H.sub.19 NO.sub.5                                                             293,31                                                                               137  58  61,42                                                                             6,53                                                                              4,78                                                                              61,27                                                                             6,56                                                                              4,66               77 0131                                                                             4 O(CH.sub.2).sub.2CN                                                                           C.sub.13 H.sub.14 N.sub.2 O.sub.4                                                      262,26                                                                               131  39  59,53                                                                             5,38                                                                              10,68                                                                             59,06                                                                             5,24                                                                              10,37              77 0126                                                                              ##STR47##       C.sub.13 H.sub.16 N.sub.2 O.sub.5                                                      280,27                                                                               164  75  55,71                                                                             5,75                                                                              10,00                                                                             55,44                                                                             5,70                                                                              10,09              77 0501                                                                             4-S CH.sub.2 CO CH.sub.3                                                                        C.sub.13 H.sub.15 NO.sub.4 S                                                           281,32                                                                               116  55  55,50                                                                             5,37                                                                              4,98                                                                              55,32                                                                             5,33                                                                              4,68               77 0328                                                                             4-NHC.sub.5 H.sub.11 n                                                                          C.sub.15 H.sub.22 N.sub.2 O.sub.3                                                      278,34                                                                               124  10  64,72                                                                             7,97                                                                              10,07                                                                             64,47                                                                             7,97                                                                              10,02              77 0155                                                                              ##STR48##       C.sub.12 H.sub.16 N.sub.2 O.sub.3                                                      236,26                                                                               110  60  61,00                                                                             6,83                                                                              11,86                                                                             61,02                                                                             6,76                                                                              11,75              77 0230                                                                             3-OCH.sub.2 CO CH.sub.3                                                                         C.sub.13 H.sub.15 NO.sub.5                                                             265,26                                                                               102  53  58,86                                                                             5,70                                                                              5,28                                                                              58,61                                                                             5,78                                                                              5,27               77 0231                                                                             3-O CH.sub.2 CN  C.sub.12 H.sub.12 N.sub.2 O.sub.4                                                      248,23                                                                               110  71  58,06                                                                             4,87                                                                              11,29                                                                             58,08                                                                             4,90                                                                              11,35              760557                                                                               ##STR49##       C.sub.17 H.sub.16 BrNO.sub.4                                                           378,27                                                                               136  70  53,98                                                                             4,26                                                                              3,70                                                                              54,07                                                                             4,25                                                                              3,71               77 0234                                                                              ##STR50##       C.sub.17 H.sub.16 N.sub.2 O.sub.6                                                      344,31                                                                               135  55  59,30                                                                             4,68                                                                              8,14                                                                              59,22                                                                             4,47                                                                              8,16               77 0318                                                                              ##STR51##       C.sub.18 H.sub.16 N.sub.2 O.sub.4                                                      324,32                                                                               135  72  66,66                                                                             4,97                                                                              8,64                                                                              66,48                                                                             4,84                                                                              8,75               77 0222                                                                              ##STR52##       C.sub.18 H.sub.16 N.sub.2 O.sub.4                                                      324,32                                                                               138  78  66,66                                                                             4,97                                                                              8,64                                                                              66,48                                                                             4,94                                                                              8,57               77 0569                                                                              ##STR53##       C.sub.19 H.sub.20 N.sub.2 O.sub.5                                                      356,37                                                                               212  50  64,03                                                                             5,66                                                                              7,86                                                                              64,33                                                                             5,69                                                                              7,79               77 0263                                                                              ##STR54##       C.sub.17 H.sub.15 Cl.sub.2 NO.sub.4                                                    368,21                                                                               140  40  55,45                                                                             4,11                                                                              3,80                                                                              55,66                                                                             4,13                                                                              3,68               77 0354                                                                              ##STR55##       C.sub.17 H.sub.15 Cl.sub.2 NO.sub.4                                                    368,21                                                                               138  36  55,45                                                                             4,11                                                                              3,80                                                                              55,70                                                                             4,19                                                                              3,84               77 0416                                                                              ##STR56##       C.sub.17 H.sub.15 Cl.sub.2 NO.sub.4                                                    368,21                                                                               135  25  55,45                                                                             4,11                                                                              3,80                                                                              55,43                                                                             4,12                                                                              3,75               77 0572                                                                              ##STR57##       C.sub.17 H.sub.15 ClFNO.sub.4                                                          351,75                                                                               110  50  58,04                                                                             4,30                                                                              3,98                                                                              57,83                                                                             4,21                                                                              3,88               77 0672                                                                              ##STR58##       C.sub.17 H.sub.15 ClN.sub.2 O.sub.6                                                    378,76                                                                               132  75  53,90                                                                             3,99                                                                              7,40                                                                              53,97                                                                             3,80                                                                              7,41               77 0790                                                                              ##STR59##       C.sub.17 H.sub.15 ClN.sub.2 O.sub.6                                                    378,76                                                                               114  22  53,90                                                                             3,99                                                                              7,40                                                                              54,27                                                                             3,76                                                                              7,49               77 0789                                                                              ##STR60##       C.sub.18 H.sub.15 FN.sub.2 O.sub.4                                                     342,32                                                                               93   49  63,15                                                                             4,42                                                                              5,18                                                                              63,54                                                                             4,58                                                                              8,23               77 0298                                                                              ##STR61##       C.sub. 16 H.sub.16 N.sub.2 O.sub.4                                                     300,30                                                                               138  33  63,99                                                                             5,37                                                                              9,33                                                                              64,05                                                                             5,44                                                                              9,44               77 0221                                                                              ##STR62##       C.sub.16 H.sub.16 N.sub.2 O.sub.4                                                      300,30                                                                               162  42  63,99                                                                             5,37                                                                              9,33                                                                              64,08                                                                             5,59                                                                              9,63               77 0299                                                                              ##STR63##       C.sub.16 H.sub.16 N.sub.2 O.sub.4                                                      300,30                                                                               144  46  63,99                                                                             5,37                                                                              9,33                                                                              64,28                                                                             5,30                                                                              9,46               77 0673                                                                              ##STR64##       C.sub.15 H.sub.15 NO.sub.4 S                                                           305,34                                                                               153  70  59,00                                                                             4,95                                                                              4,59                                                                              59,01                                                                             4,93                                                                              4,52               77 0889                                                                              ##STR65##       C.sub.15 H.sub.15 NO.sub.5                                                             289,28                                                                               162  48  62,28                                                                             5,23                                                                              4,84                                                                              62,26                                                                             5,12                                                                              4,52               76 0904                                                                             4-OCH.sub.2OCH.sub.3                                                                            C.sub.12 H.sub.15 NO.sub.5                                                             253,25                                                                               110  32  56,91                                                                             5,97                                                                              5,53                                                                              56,87                                                                             6,04                                                                              5,48               75 0601                                                                              ##STR66##       C.sub.16 H.sub.22 N.sub.2 O.sub.5                                                      322,35                                                                               121  40  59,61                                                                             6,88                                                                              8,69                                                                              59,67                                                                             6,88                                                                              8,43               77 0180                                                                             4-80.sub.5 H.sub.11 n                                                                           C.sub.15 H.sub.21 NO.sub.3 S                                                           295,39                                                                               113  73  60,99                                                                             7,17                                                                              4,74                                                                              61,15                                                                             7,06                                                                              4,87               77 0845                                                                              ##STR67##       C.sub.15 H.sub.15 N.sub.3 O.sub.4                                                      301,30                                                                               148  32  59,79                                                                             5,02                                                                              13,95                                                                             59,51                                                                             4,79                                                                              13,87              77 1181                                                                              ##STR68##       C.sub.18 H.sub.15 Cl NO.sub.3                                                          331,79                                                                               123  62  65,16                                                                             5,47                                                                              4,22                                                                              65,29                                                                             5,76                                                                              3,92               77 1263                                                                              ##STR69##       C.sub.17 H.sub.16 N.sub.2 O.sub.6                                                      344,31                                                                               142  44  59,30                                                                             4,68                                                                              8,14                                                                              59,44                                                                             4,38                                                                              7,99               77 1082                                                                              ##STR70##       C.sub.15 H.sub.21 NO.sub.4                                                             279,33                                                                               100  53  64,49                                                                             7,59                                                                              5,01                                                                              64,24                                                                             7,80                                                                              4,85               77 1246                                                                              ##STR71##       C.sub.16 H.sub.23 NO.sub.4                                                             293,35                                                                               92   22  65,50                                                                             7,90                                                                              4,78                                                                              65,53                                                                             8,12                                                                              4,64               77 1245                                                                              ##STR72##       C.sub.17 H.sub.23 NO.sub.4                                                             305,36                                                                               108  35  66,86                                                                             7,59                                                                              4,59                                                                              66,89                                                                             7,85                                                                              4,53               77 0949                                                                              ##STR73##       C.sub.18 H.sub.25 NO.sub.4                                                             319,39                                                                               84   73  67,69                                                                             7,89                                                                              4,39                                                                              67,81                                                                             7,71                                                                              4,08               77 1249                                                                              ##STR74##       C.sub.15 H.sub.21 NO.sub.4                                                             279,33                                                                               136  15  64,49                                                                             7,58                                                                              5,01                                                                              64,64                                                                             7,62                                                                              4,91               77 1197                                                                              ##STR75##       C.sub.16 H.sub.23 NO.sub.4                                                             293,35                                                                               86   82  65,50                                                                             7,90                                                                              4,78                                                                              65,20                                                                             8,16                                                                              4,07               78 0076                                                                              ##STR76##       C.sub.17 H.sub.23 NO.sub.4                                                             305,36                                                                               99   43  66,86                                                                             7,59                                                                              4,99                                                                              66,85                                                                             7,50                                                                              4,35               77 0984                                                                              ##STR77##       C.sub.17 H.sub.19 NO.sub.4                                                             301,33                                                                               128  32  67,76                                                                             6,36                                                                              4,65                                                                              67,49                                                                             6,47                                                                              4,40               78 0259                                                                              ##STR78##       C.sub.14 H.sub.16 N.sub.2 O.sub.4                                                      276,28                                                                               94   55  60,86                                                                             5,84                                                                              10,14                                                                             60,66                                                                             5,85                                                                              9,98               77 0962                                                                              ##STR79##       C.sub.14 H.sub.17 NO.sub.6                                                             295,28                                                                               154  62  56,94                                                                             5,80                                                                              4,74                                                                              56,93                                                                             5,91                                                                              4,80               78 0030                                                                              ##STR80##       C.sub.18 H.sub.25 NO.sub.4                                                             319,39                                                                               111  80  67,68                                                                             7,89                                                                              4,39                                                                              67,76                                                                             8,12                                                                              4,07               78 0080                                                                              ##STR81##       C.sub.14 H.sub.17 NO.sub.4 S.sub.2                                                     327,42                                                                               160  60  51,35                                                                             5,23                                                                              4,28                                                                              51,51                                                                             5,28                                                                              4,00               78 0112                                                                              ##STR82##       C.sub.14 H.sub.17 NO.sub.5 S                                                           311,35                                                                               118  55  54,00                                                                             5,50                                                                              4,50                                                                              54,13                                                                             5,52                                                                              4,38               77 0900                                                                              ##STR83##       C.sub.16 H.sub.21 NO.sub.5                                                             307,34                                                                               130  65  62,52                                                                             6,89                                                                              4,56                                                                              62,46                                                                             7,21                                                                              4,87               77 1301                                                                              ##STR84##       C.sub.16 H.sub.21 NO.sub.5                                                             307,34                                                                               160  72  62,52                                                                             6,89                                                                              4,56                                                                              62,29                                                                             7,02                                                                              4,43               77 1240                                                                              ##STR85##       C.sub.17 H.sub.16 I N.sub.2 O.sub.4                                                    314,33                                                                               132  88  64,95                                                                             5,77                                                                              8,91                                                                              64,71                                                                             6,00                                                                              8,71               77 1321                                                                              ##STR86##       C.sub.17 H.sub.16 I NO.sub.4                                                           425,21                                                                               145  76  48,02                                                                             3,79                                                                              3,29                                                                              47,85                                                                             3,56                                                                              3,45               78 0182                                                                              ##STR87##       C.sub.19 H.sub.20 N.sub.2 O.sub.6                                                      372,37                                                                               202  47  61,28                                                                             5,41                                                                              7,52                                                                              60,71                                                                             5,72                                                                              7,94               78 0443                                                                              ##STR88##       C.sub.20 H.sub.22 N.sub.2 O.sub.5                                                      370,39                                                                               208  32  64,85                                                                             5,98                                                                              7,56                                                                              64,78                                                                             6,04                                                                              7,70               77 0955                                                                              ##STR89##       C.sub.17 H.sub.15 FN.sub.2 O.sub.6                                                     362,31                                                                               110  82  56,35                                                                             4,17                                                                              7,73                                                                              56,16                                                                             4,40                                                                              7,43               77 1125                                                                              ##STR90##       C.sub.18 H.sub.15 N.sub.3 O.sub.6                                                      369,32                                                                               176  85  58,53                                                                             4,09                                                                              11,38                                                                             58,03                                                                             3,85                                                                              11,37              77 1199                                                                              ##STR91##       C.sub.17 H.sub.15 ClN.sub.2 O.sub.6                                                    378,76                                                                               178  78  53,90                                                                             3,99                                                                              7,40                                                                              53,47                                                                             3,90                                                                              6,72               77 0979                                                                              ##STR92##       C.sub.15 H.sub.15 NO.sub.5                                                             289,28                                                                               131  47  62,28                                                                             5,23                                                                              4,84                                                                              61,98                                                                             5,22                                                                              4,72               77 1067                                                                              ##STR93##       C.sub.15 H.sub.15 NO.sub.4 S                                                           305,34                                                                               144  23  59,00                                                                             4,95                                                                              4,59                                                                              59,04                                                                             4,98                                                                              4,43               78 0077                                                                              ##STR94##       C.sub.15 H.sub.19 NO.sub.4 S.sub.2                                                     341,44                                                                               142  58  52,76                                                                             5,61                                                                              4,10                                                                              52,98                                                                             5,85                                                                              4,02               78 0562                                                                              ##STR95##       C.sub.15 H.sub.18 N.sub.2 O.sub.4                                                      290,31                                                                               68   35  62,05                                                                             6,25                                                                              9,65                                                                              61,75                                                                             6,25                                                                              9,70               78 0564                                                                              ##STR96##       C.sub.18 H.sub.17 NO.sub.3                                                             295,32                                                                               215  71  73,20                                                                             5,80                                                                              4,74                                                                              72,92                                                                             5,72                                                                              4,66               __________________________________________________________________________

The compounds of formula (I) were studied on laboratory animals and showed activities in the psychotropic field, as potential anti-depressants.

These activities were revealed in the following tests:

Test A: Potentiation in mice of generalized trembling caused by an interperitoneal injection (200 mg/kg) of dl-5-hydroxytryptophane, following the protocol described by C. Gouret and G. Raynaud in J. Pharmacol. (Paris), (1974) 5, 231.

Test B: Antagonism with respect to the ptosis observed one hour after an intravenous injection (2 mg/kg) of reserpine given to mice, following the protocol described by C. Gouret and J. Thomas in J. Pharmacol. (Paris), (1973), 4, 401.

Test C: Reduction in the density of pontogeniculo-occipital points (P.G.O.) caused by an intravenous injection (0.5 mg/kg) of reserpine given to cats, following the protocol described by A. Coston and C. Gouret in J. Pharmacol. (Paris) (1976), 7, 409.

The results of these three tests, as well as those of a well-known reference substance, TOLOXATONE, are collected, in Table II below:

                  TABLE II                                                         ______________________________________                                                     Test A     Test B     Test C                                                   ED 50      ED 50      ED 50                                        Compounds tested                                                                           (mg/kg/p.o.)                                                                              (mg/kg/p.o.)                                                                              (mg/kg/i.p.)                                 ______________________________________                                         (a) Of the invention                                                           770 365     29         25         --                                           770 423     35         25         5                                            770 152     20         25         15                                           770 696     15         20         --                                           770 388     9          12;5       4;5                                          770 788     6;25       12;5       --                                           770 467     2;8        1;2        3                                            770 466     9;6        6;2        9                                            770 196     20         15         16                                           770 154     50         50         20                                           770 131     2;5        3          5;5                                          770 126     8          11         16;5                                         760 904     50         50         8;5                                          750 601     70         8          31                                           770 180     35         45         45                                           770 501     22         25         --                                           770 328     25         35         --                                           770 155     50         22;5       35                                           770 230     --         6;25       16                                           770 231     40         50         14                                           760 557     7;3        3;3        110                                          770 234     1;5        0;7        9                                            770 318     25         16         --                                           770 222     2;8        1;2        5;2                                          770 569     5          2;5        6                                            770 268     7          8;5        --                                           770 354     25         30         30                                           770 416     6;2        10         3                                            770 572     6;3        3;12       8;5                                          770 672     25         19         --                                           770 790     50         25         --                                           770 789     3          2          --                                           770 298     55         12;5       --                                           770 221     11;8       3;12       15                                           770 299     20         12;5       --                                           770 673     16         35         8                                            770 845     6;25       12;5       --                                           771 181     6;25       6;25       --                                           771 263     4          3;1        --                                           771 082     1;3        0;7        --                                           771 246     17         23         --                                           771 245     1;5        2          --                                           770 949     10         16         --                                           771 249     22;5       50         --                                           771 197     25         16         --                                           780 030     3          5;3        --                                           780 076     2;3        7          --                                           770 984     10         25         --                                           780 259     1;25       3;2        --                                           770 962     26         50         --                                           780 080     50         50         --                                           780 112     5          5;2        --                                           770 900     50         25         --                                           780 034     4;4        6;2        --                                           771 301     1;9        3          --                                           771 240     35         50         --                                           771 321     25         20         --                                           780 182     40         25         --                                           780 443     3;7        12;5       --                                           770 955     13         7          --                                           771 125     3;12       1;56       --                                           771 199     1;1        0;8        --                                           780 562     0;8        --         --                                           770 979     14         35         --                                           771 067     7;5        12;5       --                                           780 077     25         44         --                                           (b) Reference                                                                  TOLOXATONE  60         50         28                                           ______________________________________                                    

As can be seen from the preceding results and those given in Table III below, the difference between the lethal doses and the pharmacologically active doses is sufficient for the compounds of the invention to be used in therapeutics.

                  TABLE III                                                        ______________________________________                                                   Acute toxicity in mice                                                           Dose administered                                                                           Mortality                                                                               LD 50                                        Compounds tested                                                                           (mg/kg/p.o.) (%)      (mg/kg/p.o.)                                 ______________________________________                                         (a) Of the invention                                                           770 131     1000         0        --                                           770 222     1000         0        --                                           770 234     1000         0        --                                           760 652     1000         0        --                                           760 557     1000         0        --                                           771 082     --           --       >2000                                        771 245     --           --       >2000                                        771 301     --           --       >2000                                        770 955     2000         17       --                                           (b) Reference                                                                  TOLOXATONE  --           --        1850                                        ______________________________________                                    

As can be seen from the results shown in the preceding tables, the compounds of formula (I) have an activity greater than or equal to that of the reference compound.

They are indicated in endogenous and exogenous depressive conditions and will be administered orally in the form of tablets, pills or capsules, at a dosage of 500 mg/day on average, of active substance.

They will also be administered in the form of an injectable aqueous solution at the rate of 5-50 mg/day of active substance, the solvent used being formed by binary or ternary mixtures containing for example water, polypropyleneglycol or polyethyleneglycol (quality: 300-400), or any other physiologically acceptable solvent; the relative proportions of the different solvents being adjusted with respect to the dose administered. 

What we claim is:
 1. A compound having the formula ##STR97## in which R is selected from the group consisting of: a group having the formula ##STR98## situated in para position and in which R₃ is selected from the group consisting of 2-cyano, 3-chloro, 3-bromo, 3-nitro, 3-cyano, 4-acetamido and 4--NHCOC₂ H₅ ; and a group having the formula ##STR99## situated in para position and in which the combination of (R₄, R₅) is selected from the group consisting of (3--Cl, 4--Cl), (3--Cl, 5--Cl), (3--Cl, 4--F), (3--NO₂, 4--Cl), (3--CN, 4--F), (3--NO₂, 4--F), (3--NO₂, 5--CN) and (3--NO₂, 5--Cl).
 2. A compound as claimed in claim 1 in which R is ##STR100##
 3. A compound as claimed in claim 2 in which R is ##STR101##
 4. A compound as claimed in claim 2 in which R is ##STR102##
 5. A compound as claimed in claim 1 in which R is ##STR103##
 6. A compound as claimed in claim 5 in which R is ##STR104##
 7. A compound as claimed in claim 5 in which R is ##STR105##
 8. A compound as claimed in claim 5 in which R is ##STR106## 